Hi Anna. I would not use the Purina Outlast- because there are other things on the market that are safe for IR horses. Such as the Uckele GUT  product. I would go with the 2 cups of stabul 1 as the carrier.  Diet is something we have the most control over and its something that IR horses are exposed to every single day. So, getting the diet to be as pristine as possible for the IR horse and supporting their exercise requirements ( which you can do now with your horse) is one of the keys to successful management.... 
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Trisha DePietro
Aug 2018
NH
Primary Responder
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